Abstract: After the ‘5 ·12’ Wenchuan earthquake, Phyllite in the fault zone of the Beichuan County was used as the subgrade fill, and tests were conducted on the chemical composition. Physical property and slaking of the fractured Phyllite. Results showed that Phyllite can be used as the bottom fill of the subgrade, and its point load strength is correlated to many factors. Durability of slaking much depends on the contents of clay mineral of the fractured Phyllite, and compaction property is closely related to the relative of different particle sizes. According to the monitoring data on site, the compaction process determined by research can obtain a expected density of Phyllite and improve the physical and mechanical properties of the rocks, which meets the requirements of the subgrade.